1. Field of the Invention
This invention relates to a composition and method for cleaning and imparting antistatic properties to plastic surfaces. More particularly, this invention relates to an organic solvent-free aqueous composition or concentrate thereof for cleaning and polishing plastic substrates, particularly acrylic plastics, and other hard surfaces including vinyl, leather, formica, tile, polycarbonate and other plastic surfaces.
2. Discussion of the Prior Art
Formulations for cleaning plastic surfaces should desirably have the following properties:
(1) Nonreactive with the plastic substrate;
(2) No visible residual film or streaks;
(3) Easy wipe-off;
(4) Fast drying;
(5) Removal of oils, grease, fingerprints, fats, and other soils and dirts;
(6) Nontoxic;
(7) Impart antistatic film on surface of plastic substrate.
In order to assure nonreactivity of the cleaning composition with the plastic substrate, particularly for acrylic and polycarbonate based plastic surfaces, such as "Plexiglas", "Lucite", "Lexan" and the like, the cleaning composition should be free of organic solvents. The cleaning properties, per se, are generally provided by various anionic, nonionic, cationic and/or ampholytic surface-active agents and very broad classes of each of these types of surface-active agents have been disclosed in the art. It is also known, as disclosed for example, in U.S. Pat. No. 2,757,094 to Guss and in U.S. Pat. No. 2,955,047 to Terry to include a silicone fluid, particularly dimethylpolysiloxane, in plastic cleaning compositions to leave a thin lubricating coating on the plastic substrate to enhance the cleaning and polishing properties of the surface-active agents and to cause the treated surface to become smooth, slippery and electrostatically inert, thereby preventing the collection of dust, oil, grime and other soils on the surface.
U.S. Pat. No. 3,352,787 to Bodach teaches that the addition of an ionic surfactant, e.g., an anionic surfactant or a cationic surfactant, to a nonionic surfactant containing cleaning composition, inhibits crazing of plastic surfaces such as "Plexiglas".
Fluorinated and particularly perfluorinated surface-active materials have recently received wide attention in cleaning compositions. Zisman, et al in U.S. Pat. No. 3,498,923 discloses non-aqueous liquid surface-active compositions for displacing liquid organic films adsorbed to metal, glass, resin and polymeric surfaces, which compositions also have utility as dust repellants for said surfaces. The compositions are in the form of a solution of a small amount of a partially fluorinated long-chain alkyl monocarboxylic acid of the formula F(CF.sub.2).sub.m (CH.sub.2).sub.n COOH wherein m is an integer of from 2 to 5 and n is an integer of from 10 to 16, in a solvent which is an aliphatic naphtha having a minimum flash point of from about 108.degree. F. to 140.degree. F. or a liquid low molecular weight linear dimethyl silicone, the silicone ranging from the dimer to the octamer.
U.S. Pat. No. 3,948,819 to Wilde discloses cleaning compositions especially adapted for cleaning aluminum surfaces in which the surfactant system consists essentially of at least two nonionic polyethoxylated surfactants, the first of which contains from 35 to 55% oxyethylene units by weight, the second containing at least 55% oxyethylene units by weight but not less than 10% more oxyethylene units by weight than does the first surfactant, and an antiresoiling agent containing at least one fluoroaliphatic radical and at least one phosphate or substituted phosphate radical.
Grejsner in U.S. Pat. No. 4,269,739 discloses a composition for surface treatment and cleaning of objects, in particular records, which is an aqueous solution or emulsion of:
(A) from 0.001 to 1.2% by weight of natural or synthetic wax or wax-like substance,
(B) from 0.001 to 2.5% by weight of fluid silicone oil with lubricating activity,
(C) from 0.001 to 2.5% by weight of surface-active polysiloxane copolymer,
(D) from 0.001 to 1.2% by weight of fluorinated organic surface-active compound, and
(E) from 0.001 to 2.5% by weight of nonionic surfactant.
Requejo, one of the present inventors, has previously disclosed, in U.S. Pat. No. 4,302,348, a liquid composition for cleaning a wide variety of hard surfaces, such as metallic, plastic, tile, porcelain, glass and mirror surfaces, which composition is an improvement in the glass and mirrored surface cleaning composition described in U.S. Pat. No. 3,463,735 to Stonebraker, et al. In particular, the U.S. Pat. No. 4,302,348 patent to Requejo discloses that by adding as little as 0.011% by weight of a fluorinated hydrocarbon surfactant, and by adjusting the levels of the volatile materials in the Stonebraker compositions, a composition that functions equally well as both a glass or mirror cleaner and as a hard surface cleaner generally is achieved. Accordingly, the compositions disclosed by Requejo include at least each of a low boiling organic solvent and higher boiling organic solvent, a first surfactant that is an anionic or nonionic surfactant, a second surfactant that is an anionic or nonionic fluorinated hydrocarbon surfactant selected from the group consisting of (i) anionic fluorinated hydrocarbon surfactants wherein the fluorinated hydrocarbon portion has a branched chain structure and having aliphatic perfluorocarbon groups at one end thereof; (ii) nonionic fluorinated hydrocarbon surfactants having a fluorinated hydrocarbon portion exhibiting a branched structure and having the formula R.sub.f (OCH.sub.2 CH.sub.2).sub.n OR.sub.f or R.sub.f (OCH.sub.2 CH.sub.2).sub.m OR wherein R.sub.f is C.sub.8 F.sub.15, C.sub.10 F.sub.19 or C.sub.12 F.sub.23 ; R is a lower alkyl; n is an integer of from 10 to 30, and m is an integer of from 2 to 10, and (iii) anionic fluorinated hydrocarbon surfactants wherein the fluorinated hydrocarbon portion exhibits a straight chain structure and having aliphatic perfluorocarbon groups at one end of the chain thereof; (iv) an alkali metal polyphosphate and a fugitive alkaline material, the balance of the composition being water.
A mold release composition in the form of a solution or dispersion which includes a perfluoroalkyl group-containing phosphoric acid ester of the formula (R.sub.f YC.sub.q H.sub.2q O).sub.n PO(OH).sub.3-n wherein R.sub.f represents a perfluoroalkyl having 4 to 20 carbon atoms; Y is CH.sub.2 CH(Z), Z being H, CH.sub.3, C.sub.2 H.sub.5, Cl or OR (wherein R is H, CH.sub.3, C.sub.2 H.sub.5, COCH.sub.3, COC.sub.2 H.sub.5 or CH.sub.2 COOH or its salt, or SO.sub.2 N(R'), R' being an alkyl group having 1 to 4 carbon atoms), q is an integer of 0 to 4 and n is an integer of 1 to 3, or a salt thereof; at least one of either a noncurable polysiloxane having a boiling point of at least 100.degree. C. and a melting point not higher than 150.degree. C. or a highly fluorinated organic compound having a melting point below 150.degree. C., and surface-active agents and a liquid carrier which may be water, is disclosed by Horiuchi, et al in U.S. Pat. No. 4,118,235.
There still remains a need for improved aqueous cleaning compositions, particularly for acrylic and polycarbonate plastics such as "Plexiglas", "Lucite", "Lexan" and the like which, in addition to satisfying each of the seven properties enumerated above, are effective polishing compositions, i.e. cause scratches in the plastic surface to seemingly disappear, without effecting the clarity of these plastic surfaces which are usually transparent or at least translucent.
It is, accordingly, an object to provide an improved formulation suitable for cleaning and polishing plastic surfaces.
It is a further object of the present invention to provide a composition for cleaning, polishing and imparting antistatic properties and lubricity to plastic substrates to effectively prevent redeposition of dust, oil and other grimy deposits on the cleaned surface.
A still further object of the present invention is to provide a cleaning composition having the above properties from readily available, nontoxic and inexpensive materials.
Still yet another further object of the present invention is to provide a cleaning and polishing composition suitable for industrial use on acrylic and polycarbonate plastic substrates, such as "Plexiglas", "Lucite", "Lexan", and the like.
It is also an object of the present invention to provide a method for cleaning plastic surfaces, particularly acrylic plastic surface, by providing a composition which is simple to use and easily removed.